Liquid crystal polymer composition, liquid crystal display and method for manufacturing the same

ABSTRACT

A liquid crystal polymer composition comprising a liquid crystal, acrylic monomers including an acrylic monomer group (A) including a cyclic ring and an acrylic monomer group (B) including a chain structure or a cyclohexanol, and a photo initiator.

The present patent document is a divisional of U.S. patent applicationSer. No. 14/317,964, filed on Jun. 27, 2014, which claims the prioritybenefit to Korean Patent Application No. 10-2013-0076050 filed on Jun.28, 2013, and Korean Patent Application No. 10-2013-0085260 filed onJul. 19, 2013, which is incorporated herein by reference for allpurposes as if fully set forth herein.

BACKGROUND

Field of the Disclosure

Embodiments of the disclosure relate to a liquid crystal display (LCD),and more particularly, to a liquid crystal polymer composition capableof preventing a defect due to a change in a liquid crystal cell gap andimproving reliability by enhancing adhesive strength of a barrier rib, aliquid crystal display (LCD) device including the same, and a method formanufacturing the same.

Discussion of the Related Art

The advancement of the information-oriented society has increased demandfor display devices in various forms. Recently, various flat displaydevices such as a liquid crystal display (LCD), a plasma display panel(PDP), an organic light emitting display (OLED), and the like, have beenresearched and some of these have already been utilized as displaydevices in various equipment.

Among them, LCDs, advantageously having excellent image quality, beinglighter and thinner, and consuming a small amount of power, have beencommonly used and variously developed as monitors of televisions andcomputers that receive and display broadcast signals, as well as for aportability purpose such as monitors of notebook computers.

A general LCD device includes a thin film transistor (TFT) arraysubstrate in which TFTs and electrodes are formed, a color filtersubstrate in which R, G, and B color filters are formed, and a liquidcrystal layer injected therebetween. In the LCD, liquid crystal of theliquid crystal layer is aligned by an electric field between theelectrodes, and an image may be displayed by adjusting an amount oflight that transmits through the liquid crystal layer according to adegree of alignment of the liquid crystal. A barrier rib is formed tomaintain a predetermined interval in which the liquid crystal layer isformed between the TFT array substrate and the color filter arraysubstrate of the LCD device. The barrier rib is fixedly formed to have acolumnar shape with a predetermined height during a TFT array substratemanufacturing process.

Recently, materials of substrates have been changed from glass toplastic. However, in case of a plastic substrate, a cell gap of liquidcrystal is not maintained and seal bursts as liquid crystal concentrateson one side, or the like. Unlike glass, the plastic substrate has lowrigidity, requiring a wall maintaining upper and lower plates andpreventing concentration of liquid crystal, but current structures lackability to solve the problem.

SUMMARY

Embodiments of the invention provide a liquid crystal polymercomposition capable of maintaining a liquid crystal cell gap and solvinga problem such as seal burst, and the like, a liquid crystal display(LCD) device including the same, and a method for manufacturing thesame.

In one aspect, there is a liquid crystal polymer composition comprisinga liquid crystal, acrylic monomers including an acrylic monomer group(A) including a cyclic ring and an acrylic monomer group (B) including achain structure or a cyclohexanol, and a photo initiator.

In another aspect, there is a liquid crystal display device including aliquid crystal layer interposed between a thin film transistor (TFT)array substrate and a color filter array substrate, the liquid crystaldisplay device comprising barrier ribs positioned within the liquidcrystal layer and supporting the TFT array substrate and the colorfilter array substrate, wherein the barrier ribs are formed by curingacrylic monomers of the liquid crystal polymer composition.

In other aspect, there is a method for manufacturing a liquid crystaldisplay device, the method comprising forming a cell by attaching a thinfilm transistor (TFT) array substrate and a color filter arraysubstrate, injecting a liquid crystal polymer composition including aliquid crystal, acrylic monomers including an acrylic monomer group (A)including a cyclic ring and an acrylic monomer group (B) including achain structure or a cyclohexanol, and a photo initiator into the cell,and irradiating UV light to the cell to cure the acrylic monomers toform barrier ribs.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIGS. 1 to 5 are views illustrating a liquid crystal display (LCD)device having various structures according to an embodiment of thepresent invention.

FIGS. 6A to 6F are views illustrating sequential processes of a methodfor manufacturing a liquid crystal display (LCD) device according

FIGS. 7A to 7D are images of barrier ribs formed by usingisodecylacrylate and isobornyl acrylate according to Embodiment 1 of thepresent invention.

FIGS. 8A to 8D are images of barrier ribs formed by using 3,3,5trimethylcyclohexanol acrylate and isobornyl acrylate according toEmbodiment 1 of the present invention.

FIGS. 9A to 9D are images of barrier ribs formed by using octyldecylacrylate and isobornyl acrylate according to Embodiment 1 of the presentinvention.

FIGS. 10A to 10D are images of barrier ribs formed by usingtridecylacrylate and isobornyl acrylate according to Embodiment 1 of thepresent invention.

FIGS. 11A to 11D are images of barrier ribs formed by using2-ethylhexylacrylate and isobornyl acrylate according to Embodiment 1 ofthe present invention.

FIGS. 12A and 12B are images of barrier ribs formed according toEmbodiment 2 of the present invention.

FIGS. 13A and 13B are graphs illustrating the content of residualmonomer according to Embodiment 3 of the present invention.

FIGS. 14A and 14B are images of barrier ribs formed at UV exposuretemperatures according to Embodiment 3 of the present invention.

FIGS. 15A to 15C are images of barrier ribs respectively formed at UVexposure temperatures of 35° C., 45° C., and 55° C. according toEmbodiment 3 of the present invention.

FIG. 16 is a graph illustrating modulus of barrier ribs respectivelymeasured at UV exposure temperatures of 35° C., 45° C., and 55° C.according to Embodiment 3 of the present invention.

FIGS. 17A to 17C are images of barrier ribs after first UV light wasirradiated, left at room temperature, and second UV light wassubsequently irradiated according to Embodiment 4.

FIGS. 18A and 18B are images of barrier ribs after first UV light wasirradiated and second UV light was subsequently irradiated according toEmbodiment 4.

FIGS. 19A to 19C are images illustrating a liquid crystal layerimmediately after UV irradiation and a liquid crystal layer three hoursafter the UV irradiation according to Embodiment 5.

FIG. 20 is a graph illustrating the content of residual monomer of theliquid crystal layer according to conditions of the second UVirradiation according to Embodiment 6.

FIGS. 21A to 21E are graphs illustrating test results of adhesivestrength according to Embodiment 7 of the present invention.

FIGS. 22A to 22D are images of barrier ribs of LCDs manufacturedaccording to Embodiment 8 of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Reference will now be made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts. It will be paid attentionthat detailed description of known arts will be omitted if it isdetermined that the arts can mislead the embodiments of the invention.

A liquid crystal polymer composition according to the embodiment of thepresent invention includes a liquid crystal, acrylic monomers includingan acrylic monomer group A including a cyclic ring and an acrylicmonomer group B including a chain structure or cyclohexanol, and a photoinitiator.

A nematic, smetic, or cholesteric liquid crystal may be used as theliquid crystal used in the liquid crystal polymer composition accordingto the embodiment of the present invention, and types of liquid crystalare not particularly limited.

The acrylic monomers according to the embodiments include an acrylicmonomer group A including a cyclic ring and an acrylic monomer group Bincluding a chain structure or cyclohexanol. Here, the acrylic monomergroup A including a cyclic ring includes isobornyl acrylate, orisobornyl methacrylate. The acrylic monomer group A including a cyclicring is cured later to provide rigidity of a barrier rib.

Also, the acrylic monomer group B including a chain structure orcyclohexanol includes one or more selected from the group consisting of2-methylheptyl acrylate, isodecyl acrylate, octyldecyl acrylate,tridecyl acrylate, 2-2-ethylhexyl acrylate, and lauryl acrylate. Theacrylic monomer group B including a chain structure or cyclohexanolserves to provide patternability (or pattern characteristics) to thebarrier rib.

When UV light is irradiated, the liquid crystal and the acrylic monomersof the acrylic polymer are separated in phase and the acrylic monomersare cured to form a bonding layer. Also, since only a small amount ofacrylic polymers is contained in the liquid crystal polymer composition,a small amount of uncured monomers remain, obtaining excellentreliability.

The liquid crystal polymer composition according to the embodiment ofthe present invention includes a photo initiator. As the photoinitiator, all the photo initiators such as a free radical photoinitiator, a cation photo initiator, and the like, may be used.Specifically, for example, the photo initiator may be one or moreselected from the group consisting of2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1),phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide,bis(.eta.5-2,4-cylcopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide,2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one,2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone,1-[9-ethyl-6-(2-methylbenzoyl)-9Hcarbazol-3-yl]-1, 1-(O-acetyloxime),1-hydroxy-cyclohexyl-phenyl-ketone, oxy-phenyl-acetic acid 2-[2 oxo-2phenyl-acetoxy-ethoxy]-ethyl ester,2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone),2,4,6-trimethylbenzoyldiphenylphosphine oxide,2-hydroxy-2-methyl-1-phenyl-propan-1-one), and2,2-Dimethoxy-1,2-diphenylethan-1-one.

In the liquid crystal polymer composition according to the embodiment ofthe present invention, the liquid crystal, the acrylic monomers, and thephoto initiator are contained in predetermined content ratios. A contentratio between the liquid crystal and the acrylic monomers may be 8:2 to9:1. Here, in the case in which the content ratio between the liquidcrystal and the acrylic monomers is 8:2, when the content of the acrylicmonomers is 2 or less, a degradation of reliability of liquid crystaldriving due to residual uncured monomers in a liquid crystal layer maybe prevented, and in the case in which the content ratio between theliquid crystal and the acrylic monomer is 9:1, if the content of theacrylic monomers is 1 or more, reliability of barrier ribs formed of theacrylic monomers may be enhanced.

Also, in the acrylic monomers, a content ratio between the acrylicmonomer group A including a cyclic ring and the acrylic monomer group Bincluding a chain structure or cyclohexanol may be 8:2 to 9:1. Here, theacrylic monomer group A including a cyclic ring provides rigidity of abarrier rib, and the acrylic monomer group B including a chain structureor cyclohexanol provides pattern characteristics to a barrier rib, andin this case, the content ratio therebetween needs to be appropriatelyadjusted.

Also, a content ratio between the acrylic monomers and the photoinitiator may be 7:3 to 9:1. If the content of the photo initiator issmall, monomers may not be reacted to remain, and if the content of thephoto initiator is large, the photo initiator may not be reacted toremain. Thus, the content ratio between the acrylic monomers and thephoto initiator needs to be appropriately adjusted within a range inwhich the acrylic monomers and the photo initiator do not remain.

The foregoing liquid crystal polymer composition according to theembodiment of the present invention is injected into a liquid crystaldisplay (LCD) device to form a liquid crystal and a barrier rib.Hereinafter, an LCD device formed of the liquid crystal polymercomposition and a method for manufacturing the same will be described.

FIGS. 1 to 5 are views illustrating a liquid crystal display (LCD)device having various structures according to an embodiment of thepresent invention. Hereinafter, basic components of the LCD will bedescribed with reference to FIG. 1, and only components different fromthose of FIG. 1 will be described with reference to FIGS. 2 and 5.

Referring to FIG. 1, in the LCD device 100, a gate line 120 ispositioned on the lower substrate 115. The gate line 120 acts as a gateelectrode by itself. A gate insulating layer 125 is positioned on thegate line 120, and a semiconductor layer 130 is positioned in a regioncorresponding to the gate line 120. A source electrode 135 a and a drainelectrode 135 b are connected to both sides of the semiconductor layer130, and a protective layer 140 is positioned to cover them.

An organic insulating layer 150 including a contact hole 155 exposingthe drain electrode 135 b is positioned on the lower substrate includingthe protective layer 140, and a pixel electrode 160 is positioned on theorganic insulating layer 150. The pixel electrode 160 is connected tothe drain electrode 135 b through the contact hole 155. A passivationlayer 165 is positioned on the lower substrate 115 including the pixelelectrode 160, and a common electrode 170 corresponding to the pixelelectrode 160 is positioned on the passivation layer 165. A TFT arraysubstrate 110 including a structure from the lower substrate 115 to thecommon electrode 170 is formed.

Meanwhile, an upper substrate 215 is positioned on the TFT arraysubstrate 110. Black matrices 220 are positioned on the upper substrate215, and R, G, and B color filters 225 are positioned between the blackmatrices. An overcoat layer 230 is positioned to cover the blackmatrices 220 and the color filters 225, forming a color filter arraysubstrate 210. A liquid crystal layer 180 is positioned between the TFTarray substrate 110 and the color filter array substrate 210, and abarrier rib 184 for maintaining a gap of the liquid crystal layer 180 ispositioned to form the LCD device 100 according to the presentinvention. The liquid crystal layer 180 and the barrier rib 187 of theLCD device 100 as described above are formed of the liquid crystalpolymer composition of the present invention as described above. Aspecific manufacturing process will be described hereinbelow.

Meanwhile, the barrier rib 185 of the present invention is in contactwith flat surfaces between the TFT array substrate 110 and the colorfilter array substrate 210. However, the barrier rib 185 according tothe present invention may have any other contact structure.

Referring to FIG. 2, the barrier rib 185 is in contact with a thirdrecess 250 and a fourth recess 260 formed in the passivation layer 165.In detail, during a process of forming the contact hole 155 in theorganic insulating layer 150 formed on the lower substrate 115, thefirst recess 240 is formed. The first recess 240 is formed to correspondto the gate line 120. When a silicon nitride (SiNx) is deposited on theorganic insulating layer 150 through chemical vapor deposition (CVD) toform the passivation layer 165, the third recess 250 and the fourthrecess 260 are formed in accordance with the lower step of thepassivation layer 165. Thus, when UV light is irradiated to a liquidcrystal polymer composition in a follow-up process, the barrier rib 185is formed to be in contact with the third and fourth recesses 250 and260.

Also, referring to FIG. 3, in addition to the foregoing structure ofFIG. 2, the barrier rib 185 is in contact with a fifth recess 280 formedin the overcoat layer 230 of the color filter array substrate 210. Thefifth recess 280 is positioned in a region corresponding to the firstrecess 240. Thus, the barrier rib 185 is formed to be in contact withthe fifth recess 280 of the color filter array substrate 210 and thethird and fourth recesses 250 and 26 of the TFT array substrate 110.

Meanwhile, referring to FIG. 4, the barrier rib 185 is in contact withthe third recess 250, the fourth recess 260, and a sixth recess 270formed in the passivation layer 165. In detail, during a process offorming the contact hole 155 in the organic insulating layer 150 formedon the lower substrate 115, the first recess 240 and the second recess245 are formed. The first recess 240 is formed to correspond to the gateline 120, and the second recess 245 is formed alongside of the firstrecess 240. When silicon nitride (SiNx) is deposited on the organicinsulating layer 150 through CVD to form the passivation layer 165, thethird recess 250, the fourth recess 260, and the sixth recess 270 areformed in accordance with a lower step of the passivation layer 165.Thus, when UV light is irradiated to the liquid crystal polymercomposition in a follow-up process, the barrier rib is formed to be incontact with the third recess 250, the fourth recess 260, and the sixthrecess 270.

Also, referring to FIG. 5, the barrier rib 185 is further in contactwith the fifth recess 280 formed on the overcoat layer 230 of the colorfilter array substrate 210 in addition to the foregoing structure ofFIG. 4. The fifth recess 280 is positioned in a region corresponding tothe foregoing first recess 240. Thus, the barrier rib 185 is formed incontact with the fifth recess 280 of the color filter array substrate310 and the third recess 250, the fourth recess 260, and the sixthrecess 270 of the TFT array substrate 110.

As described above, in the LCD device according to the embodiment of thepresent invention, the barrier rib is formed by irradiating UV light tothe liquid crystal polymer composition and a plurality of recesses areformed in the region in which the barrier rib is formed to increase aneffective area in which the barrier rib is in contact, thus enhancingadhesive strength of the barrier rib.

A method for manufacturing the LCD device having the foregoing structurewill be described with reference to FIGS. 6A to 6F. In the belowdescription, the structure of FIG. 5 including all the processes of theLCD device having the various structures as described above will betaken as an example.

Referring to FIG. 6A, a lower substrate 115 is formed on a first supportsubstrate 50. The first support substrate 50 is a glass substrate, andthe lower substrate 115 is formed of polyimide (PI). A gate line 120 isformed on the lower substrate 115. The gate line 120 may be a singlelayer formed of aluminum (Al), molybdenum (Mo), tungsten (W), titanium(Ti), or an alloy thereof, or may be formed as multiple layers includingmolybdenum/aluminum/molybdenum (Mo/Al/Mo) or titanium/aluminum/titanium(Ti/Al/Ti). A gate insulating layer 125 is formed on the gate line 120.The gate insulating layer 125 may be formed of a silicon oxide (SiOx), asilicon nitride (SiNx), or a stacked structure of a silicon oxide (SiOx)and a silicon nitride (SiNx).

A semiconductor layer 130 is formed on the gate insulating layer 125.The semiconductor layer 130 may be formed of an amorphous silicon layer,a polycrystalline silicon layer obtained by crystallizing an amorphoussilicon layer, or an oxide semiconductor formed of a metal oxide. Asource electrode 135 a and a drain electrode 135 b are formed on bothsides of the semiconductor layer 130. The source electrode 135 a and thedrain electrode 135 b may be formed of the same material as that of theforegoing gate line 120. A protective layer 140 is formed on the sourceelectrode 135 a and the drain electrode 135 b. The protective layer 140may be formed of a silicon oxide (SiOx), a silicon nitride (SiNx), or astacked structure of a silicon oxide (SiOx) and a silicon nitride(SiNx).

Subsequently, referring to FIG. 6B, an organic insulating layer 150 isformed on the lower substrate 115 with the protective layer 140 formedthereon, and a contact hole 155, a first recess 240 and a second recess245 are formed on the organic insulating layer 150 throughphotolithography using photoresist PR. The organic insulating layer 150is formed of an organic substance such as polyimide, benzocyclobuteneseries resin, acrylate, or the like. In this case, the contact hole 155is formed to expose the drain electrode 135 b, the first recess 24 isformed in a region corresponding to the gate line 120, and the secondrecess 245 is formed alongside of the first recess 240.

Thereafter, referring to FIG. 6C, a pixel electrode 160 is formed on theorganic insulating layer 150 with the first recess 240 and the secondrecess 245 formed t hereon. The pixel electrode 160 may be formed of atransparent conductive layer such as ITO, IZO, or the like. Apassivation layer 165 is formed on the lower substrate 115 with thepixel electrode 160 formed thereon. Since a silicon oxide or a siliconnitride is deposited through CVD, the passivation layer 165 is formed inaccordance with the lower steps. Thus, the passivation layer 165 has afourth recess 250 corresponding to the first recess 240 formed in thelower organic insulating layer 150, a sixth recess 270 corresponding tothe second recess 245, and a fourth recess 260 corresponding to thecontact hole 155. Subsequently, a common electrode 170 corresponding tothe pixel electrode 160 is formed on the passivation layer 165 to form aTFT array substrate 110.

Subsequently, referring to FIG. 6D, an upper substrate 215 is formed ona second support substrate 60, and black matrices 220 are patterned tobe formed on the upper substrate 215. R, G, and B color filters 225 areformed in pixel regions demarcated by the black matrices 220, and anovercoat layer 230 is formed thereon. A partial region of the overcoatlayer 230, namely, a region corresponding to the gate line is patternedto form a fifth recess 280 to form a color filter array substrate 210.

Thereafter, referring to FIG. 6E, the manufactured TFT array substrate110 and the color filter array substrate 210 are attached, and theliquid crystal polymer composition according to the embodiment of thepresent invention as described above is injected therebetween to form aliquid crystal layer 180 to form a cell. In this case, the liquidcrystal polymer composition includes a liquid crystal, acrylic monomersincluding an acrylic monomer group A including a cyclic ring and anacrylic monomer group B including a chain structure or cyclohexanol, anda photo initiator.

After the injecting of the liquid crystal polymer composition isfinished, UV light is irradiated to the liquid crystal layer 180 fromabove the color filter array substrate 210. When UV light is irradiated,the liquid crystal and the acrylic monomers of the liquid crystalpolymer composition are separated in phase and the acrylic monomers arecured to form a barrier rib. Thus, as illustrated in FIG. 6F, a barrierrib 185 is formed in the region to which UV light is irradiated. Thebarrier rib 185 is formed to be in contact with the fifth recess 280 ofthe color filter array substrate 210 and the third recess 250, thefourth recess 260, and the sixth recess 270 of the TFT array substrate110. Thereafter, the first support substrate 50 and the second supportsubstrate 60 are removed.

Here, the UV irradiation includes a first UV irradiation process, a roomtemperature leaving process, and a second UV irradiation process. Thefirst UV irradiation process is a process for separating a phase ofacrylic monomer, during which UV is irradiated for 5 to 60 minutes atintensity of illumination ranging from 1 to 20 mW. In this case, knownUV lamps are used for UV irradiation, and preferably, a mercury lamp isused. Also, during UV irradiation, intensity of illustration ranges from1 to 20 mW. Here, when intensity of illumination is 1 mW or greater, atime duration in which phase separation occurs to cure acrylic monomersmay be shortened, and when intensity of illumination is 20 mW or lower,a degradation of patternability as curing occurs before phase separationmay be prevented.

The room temperature leaving process is a process during which theacrylic monomers are left to be phase-separated and cured continuouslyafter the first UV irradiation process is finished. In this case, a timeduration in which the acrylic monomers may be left for 6 to 200 minutes.Here, when the time duration in which the acrylic monomers are left is60 or more, the patternability of the barrier ribs may be enhanced, andwhen the time duration in which the acrylic monomers are left is 200 orless, monomers may be prevented from agglomerating to be round.

The second UV irradiation is a process of completing curing of theacrylic monomers, which is performed for 1 to 20 minutes at an intensityof illumination ranging from 50 to 1500 mW. During the second UVirradiation, preferably, a mercury lamp is used. Here, the second UVirradiation may be performed for 1 to 20 minutes. When the second UVirradiation time is 1 minute or more, residual monomers existing in theliquid crystal layer may be reduced, and when the second UV irradiationtime is 20 minutes or less, monomers may be completely cured and a tacttime may be reduced. In this case, a temperature is maintained at 60° C.or lower during the second UV irradiation process to prevent monomersfrom being damaged by heat to deform barrier ribs.

As described above, the UV irradiation process includes the first UVirradiation process, the room temperature leaving process, and thesecond UV irradiation process. UV intensity of illumination orirradiation time is specified in each process, but the present inventionis not limited thereto and an irradiation time, or the like, may varydepending on UV irradiation conditions.

Thus, since the barrier rib 185 supportedly bonds the color filter arraysubstrate 210 and the TFT array substrate 110, a liquid crystal cell gapis maintained and a seal burst, or the like, may be prevented.

Hereinafter, preferred embodiments will be described to helpunderstanding of the present invention. However, the followingembodiments are merely illustrative and the present invention is notlimited thereto.

Embodiment 1: Evaluation of Barrier Rib According to Acrylic PolymerMaterial

A liquid crystal cell was manufactured by injecting a liquid crystalpolymer composition between two substrates. In this case, in the liquidcrystal polymer composition, materials of acrylic polymer and photoinitiator, besides the liquid crystal, were varied, and content ratiosbetween the acrylic monomer group A including a cyclic ring and anacrylic monomer group B including a chain structure or cyclohexanol,content ratios between the liquid crystal and the acrylic monomers, andcontent ratios between the acrylic polymer and the photo initiator werevaried. UV light was irradiated to the liquid crystal cell with theintensity of illumination of 17.6 mW for approximately ten minutes tophase-separate the liquid crystal and the acrylic polymer to manufacturea barrier rib.

Here, FIGS. 7A to 7D show barrier ribs manufactured by using isodecylacrylate and isobornyl acrylate as acrylic polymers. FIGS. 8A to 8D showbarrier ribs manufactured by using 3,3,5 trimethyl cyclohexanol acrylateand isobornyl acrylate. FIGS. 9A to 9D show barrier ribs manufactured byusing octyldecyl acrylate and isobornyl acrylate. FIGS. 10A to 10D showbarrier ribs manufactured by using tridecyl acrylate and isobornylacrylate. FIGS. 11A to 11D show barrier ribs manufactured by using2-ethylhexyl acrylate and isobornyl acrylate.

Table 1 show the abbreviations used in FIGS. 7A to 11D, in which eachnumber denotes a content ratio, and content of the photo initiator werevaried by 10%, 20%, and 30% over the content of acrylic monomers.

TABLE 1 A Isodecyl Acrylate B 3,3,5 Trimethyl Cyclohexanol acrylate CIso-bornyl Acrylate D Octyldecyl Acrylate E Tridecyl Acrylate F2-Ethylhexyl acrylate LC Liquid crystal M Acrylic monomer PI Photoinitiator Dar-1173 2-Hydroxy-2-methyl-1-phenyl-propan-1-one Irg-29592-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1- propanone Irg-6512,2-Dimethoxy-1,2-diphenylethan-1-one

Referring to FIGS. 7A to 11D, formation of barrier ribs are affected bymaterials and content ratios of acrylic monomers, content ratios betweenthe liquid crystal and the acrylic monomers, and materials and contentratios of photo initiators.

Embodiment 2: Evaluation of Barrier Rib According to Content of PhotoInitiator

A liquid crystal cell was manufactured by injecting a liquid crystalpolymer composition between two substrates. In this case, the liquidcrystal polymer composition included a liquid crystal, isobornylmetacrylate and isodecyl acrylate as acrylic polymers, and2,2-dimethoxy-1,2-diphenylethane-1-one. Here, barrier ribs weremanufactured by fixing a content ratio of the acrylic polymers to 9:1, acontent ratio between liquid crystal and the acrylic polymers to8.5:1.5, and varying a content ratio of the photo initiator from 0.05%to 1.5% over the content of acrylic polymers, which is shown in FIG.12A. Also, barrier ribs were manufactured by varying a content ratio ofthe liquid crystal and the acrylic polymers from 6.5:3.5 to 9:1 in astate in which a content of the photo initiator was fixed to 0.5%, whichis shown in FIG. 12B.

Referring to FIG. 12A, it was confirmed that when the contents of thephoto initiator were 0.05%, 0.1%, and 0.15%, the barrier ribs wereuncured. Also, referring to FIG. 12B, it was confirmed that when thecontent ratios between the liquid crystal and the acrylic polymers were6.5:3.5 and 7.5:2.5, the barrier ribs were uncured and a ratio of8.5:1.5 was optimal.

Embodiment 3: Evaluation of Residual Acrylic Monomers Over UVIllumination and Exposure Time

A liquid crystal cell was manufactured by injecting a liquid crystalpolymer composition between two substrates. In this case, in the liquidcrystal polymer composition, a methylheptyl acrylate and isobornylmethacrylate were used as acrylic polymers and2,2-dimethyoxy-1,2-diphenylethane-1-one was used as a photo initiator.Barrier ribs were manufactured by varying UV illumination and curingtime, and the content of acrylic monomers remaining in the liquidcrystal layer was measured and the results are shown in FIGS. 13A and13B, and also measured by varying UV exposure temperatures and theresults are shown in FIGS. 14A and 14B. Also, barrier ribs at theexposure temperatures of 35° C., 45° C., and 55° C. are showed in FIGS.15A to 15C, and modulus was measured and showed in FIG. 16 and Table 2.

Here, a reduction rate (%) in FIGS. 14A and 14B was calculated by(1−#2)/#1)×100. Under #1 condition, UV intensity of illumination was17.6 mW and it was masked with a mask and UV was irradiated for 30minutes. Under #2 condition, UV intensity of illumination was 17.6 mW,it was masked with a mask, UV was irradiated, and UV was additionallyirradiated to the entire surface for 30 minutes.

First, referring to FIGS. 13A and 13B, it was configured that, aconversion ratio was increased at low UV illumination, reducing residualmonomers. Also, referring to FIGS. 14A and 14B, there was no particularchange in residual monomers according to irradiation temperatures. Theresults of analyzing the content of residual monomers according to UVcuring conditions #1 and #2 confirmed that residual monomers werereduced by 60 to 70% under #2 condition in which UV was irradiated tothe entire surface, compared to #1 condition.

TABLE 2 Irradiation Restoration temperature Modulus rate (L) (Mpa) (%)35 2.46 × 10⁴ 10 45 4.36 × 10⁴ 13 55 3.31 × 10⁴ 13

Referring to FIGS. 15A to 15C, 16, and Table 2, it was confirmed thatoptimal texture was obtained at 45° C. in terms of patterncharacteristics of the barrier ribs according to UV irradiationtemperatures, and the highest modulus value was obtained under the samecondition. It was confirmed that, in line with the increase in themodulus value, diffusion energy of monomers was increased due to anincrease in an ambient temperature to increase cross-linking density.Meanwhile, it was confirmed that, after a temperature of 55° C. densityof barrier ribs was rather lowered due to high diffusion energy,relative to cross-linking.

Embodiment 4: Evaluation of Residual Acrylic Monomers According toManufacturing Method

A liquid crystal layer was formed with a liquid crystal polymercomposition identical to the composition of Embodiment 3 describedabove. Barrier ribs were formed according to the following methods.

First method (#1): After a cell was masked with a mask, to which UV wasirradiated by a mercury lamp with intensity of illumination of 10 mW for5 minutes (first UV irradiation) and left at room temperature for 60minutes. Subsequently, the mask was removed and UV with intensity ofillumination of 1000 mW was irradiated to the entire surface of the cellfor 5 minutes (second UV irradiation). Here, images of the barrier ribsafter the first UV irradiation, after being left at room temperature,and after the second UV irradiation are illustrated in FIGS. 17A to 17C,and the content of residual monomers after the first UV irradiation andthe second UV irradiation is illustrated in Table 3.

Second method (#2): After a cell was masked with a mask, to which UV wasirradiated by a mercury lamp with intensity of illumination of 17.6 mWfor 30 minutes (first UV irradiation), the mask was removed, and UV withintensity of illumination of 17.6 mW was irradiated to the entiresurface of the cell for 30 minutes (second UV irradiation). Here, imagesof the barrier ribs after the first UV irradiation and after the secondUV irradiation are illustrated in FIGS. 18A and 18B, and the content ofresidual monomers after the first UV irradiation and the second UVirradiation is illustrated in Table 3.

TABLE 3 After first After second UV irradiation UV irradiation #1Content of residual 2.35 0.51 monomers (%) Tack time (min.) 5 5 #2Content of residual 1.57 0.52 monomers (%) Tack time (min.) 30 30

Referring to Table 3 and FIGS. 18A and 18B, the barrier ribs formedaccording to the second method (#2) do not have good patternability andthe content of residual monomers in the liquid crystal layer was 0.52%.In contrast, referring to FIGS. 17A to 17C, the barrier ribs formedaccording to the first method (#1) have significantly improvedpatternability and the content of residual monomers in the liquidcrystal layer was 0.51%. Thus, it can be confirmed that barrier ribshaving excellent patternability are manufactured and a tact time isreduced through the first method (#1).

Embodiment 5: Observation of Images of Liquid Crystal Layer in First UVIrradiation, Immediately after Exposure According to Irradiation Energy,and Three Hours after the Exposure

A liquid crystal layer was formed with a liquid crystal polymercomposition identical to that of Embodiment 3 as described above, and UVwas irradiated according to the following methods.

First method: After a cell was masked with a mask, UV was irradiated bya mercury lamp with intensity of illumination of 8 mW by varying UVirradiation energy to 2.4 J, 4.8 J, and 7.2 J (First UV irradiation).

Second method: After a cell was masked with a mask, UV was irradiated bya mercury lamp with intensity of illumination of 16 mW by varying UVirradiation energy to 4.8 J, 9.6 J, and 14.4 J (First UV irradiation).

Third method: After a cell was masked with a mask, UV was irradiated bya mercury lamp with intensity of illumination of 22 mW by varying UVirradiation energy to 6.6 J, 13.2 J, and 19.8 J (First UV irradiation).

Images of the liquid crystal layer immediately after the UV irradiation,and three hours after the exposure are illustrated in FIGS. 19A to 19C.Referring to FIGS. 19A to 19C, it can be seen that barrier ribs arepatterned three hours after the exposure, relative to immediately afterthe exposure according to UV irradiation energy. Namely, it can beconfirmed that, when the cell is left at room temperature for apredetermined period of time after UV exposure, monomers and the liquidcrystal are effectively separated in phase.

Embodiment 6: Evaluation of Content of Residual Monomer According toSecond UV Irradiation after First UV Irradiation

A liquid crystal layer was formed with a liquid crystal polymercomposition identical to that of Embodiment 3 as described above, a cellwas masked with a masked, and subsequently, UV was first irradiated by amercury lamp with intensity of illumination of 10 mW for 5 minutes.Thereafter, barrier ribs were formed according to the following methods.

First method (#1): UV was irradiated to the entire surface of the cellwithout a mask by a mercury lamp with intensity of illumination of 17.6mW by varying irradiation duration to 1, 5, 10, 21, 31, 63, and 126minutes, in order to form barrier ribs.

Second method (#2): UV was irradiated to the entire surface of the cellwithout a mask by a mercury lamp with intensity of illumination of 77 mWby varying irradiation duration to 13, 65, 130, 270, and 360 seconds, inorder to form barrier ribs.

Third method (#3): UV was irradiated to the entire surface of the cellwithout a mask by a mercury lamp with intensity of illumination of 1500mW by varying irradiation duration to 13, 65, 130, and 240 seconds, inorder to form barrier ribs.

The content of residual monomers in the liquid crystal layer accordingto the first method as described above was measured and shown in Table4, and the content of residual monomers in the liquid crystal layeraccording to the second and third methods as described above wasmeasured and shown in Table 5, which are shown as a graph in FIG. 20.

TABLE 4 UV intensity 17.6 mW of illumination Irradiation duration 1 5 1021 31 63 126 (min) Content of residual 3.37 2.39 1.97 1.39 0.92 0.550.31 monomers (%)

TABLE 5 #2 #3 UV intensity 77 mW 1500 mW of illumination Irradiation on13 65 130 270 360 13 65 130 240 duration (s) Content of residual 3.432.75 2.69 1.87 1.58 3.92 2.35 1.67 0.51 monomers (%)

Referring to Table 4, Table 5, and FIG. 20, in the case of the firstmethod in which UV was irradiated with intensity of illumination of 17.6mW for 63 minutes, the content of residual monomers was 0.55%, and inthe case of the second method in which UV was irradiated with intensityof illumination of 77 mW for 360 minutes, the content of residualmonomers was 1.58%. In contrast, in the case of the third method inwhich UV was irradiated with intensity of illumination of 1500 mW for240 minutes, the content of residual monomers was 0.51%. Namely, sincethe UV irradiation time is reduced with high intensity of illumination,a process tack time can be reduced.

Embodiment 7: Evaluation of Adhesive Strength of Barrier Rib Formed ofLiquid Crystal Polymer Composition

A liquid crystal cell was manufactured by injecting a liquid crystalpolymer composition between two substrates. In this case, In this case,in the liquid crystal polymer composition, a methylheptyl acrylate andisobornyl methacrylate were used as acrylic polymers and2,2-dimethyoxy-1,2-diphenylethane-1-one was used as a photo initiator.Here, a content of the acrylic polymers was 9:1, and a content ratiobetween the liquid crystal and the acrylic polymers were 8.5:1.5, and acontent ratio of the photo initiator was set to 0.5% over the content ofthe acrylic polymers. UV light was irradiated to liquid crystal cells tophase-separate liquid crystal and the acrylic polymers to manufacturebarrier ribs. In this case, four 4-inch cells and one 9.7-inch cell weremanufactured. A peeling test was performed to peel out an upper plate ina 90° direction by using UTM equipment to measure adhesive strength,which is shown in Table 6 and FIGS. 21A to 21E.

TABLE 6 UV Adhesive strength dose (N/cm) 4 inch cell 31.7 J 0.03 0.050.03 0.03 9.7 inch cell   0.06

Referring to Table 6 and FIGS. 21A to 21E, it was confirmed thatadhesive strength of 0.03 N/cm was obtained in evaluating adhesivestrength.

Embodiment 8: Manufacturing of Liquid Crystal Display Device

A gate line, a gate insulating layer, a semiconductor layer, a sourceelectrode, and a drain electrode were formed on a substrate, an organicinsulating layer was coated on a protective layer covering the resultantstructure, a contact hole and a first recess were formed, a pixelelectrode was formed, a passivation layer was formed, and third andfourth recesses were subsequently formed in the passivation layer.Thereafter, black matrices and color filters were formed on thesubstrate and an overcoat layer was formed to manufacture a color filterarray substrate, the color filter array substrate were attached with aTFT array substrate, and a liquid crystal polymer composition wassubsequently injected therebetween. The liquid crystal polymercomposition was prepared and the process of manufacturing barrier ribswas performed under the same conditions as those of Embodiment 7described above to manufacture an LCD device having the structure ofFIG. 2. Barrier ribs of the LCD device manufactured thusly wereobserved. FIGS. 22A to 22D show the results.

Referring to FIG. 22A, it was confirmed that barrier ribs were formedalong gate lines on the TFT array substrate, and referring to FIGS. 22Bto 22D, it was confirmed that barrier ribs were formed, filling thethird and fourth recesses of the passivation layer.

As described above, since the barrier ribs having excellent adhesivestrength and reliability by using the new liquid crystal polymercomposition according to the embodiment of the present invention, aliquid crystal cell gap may be maintained and a seal burst may beprevented. Thus, an LCD device and a method for manufacturing the samecapable of enhancing a production yield and productivity of products maybe provided.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the scope of the principles of thisdisclosure. More particularly, various variations and modifications arepossible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A liquid crystal polymer composition comprising:a liquid crystal; acrylic monomers including an acrylic monomer group(A) including a cyclic ring and an acrylic monomer group (B) including acyclohexanol; and a photo initiator.
 2. The liquid crystal polymercomposition of claim 1, wherein the acrylic monomer group A including acyclic ring comprises one of isobornyl acrylate or isobornylmethacrylate.
 3. The liquid crystal polymer composition of claim 1,wherein the acrylic monomer group (B) including cyclohexanol comprises3,3,5 trimethyl cyclohexanol acrylate.
 4. The liquid crystal polymercomposition of claim 1, wherein a content ratio between the liquidcrystal and the acrylic monomers is 8:2 to 9:1.
 5. The liquid crystalpolymer composition of claim 4, wherein, in the acrylic monomers, acontent ratio between the acrylic monomer group (A) and the acrylicmonomer group (B) is 8:2 to 9:1.
 6. The liquid crystal polymercomposition of claim 5, wherein a content ratio between the acrylicmonomers and the photo initiator is 7:3 to 9:1.
 7. The liquid crystalpolymer composition of claim 1, wherein the photo initiator comprisesone selected from the group consisting of2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1),phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide,bis(.eta.5-2,4-cylcopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide,2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one,2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone,1-[9-ethyl-6-(2-methylbenzoyl)-9Hcarbazol-3-yl]-, 1-(O-acetyloxime),1-hydroxy-cyclohexyl-phenyl-ketone, oxy-phenyl-acetic acid 2-[2 oxo-2phenyl-acetoxy-ethoxy]-ethyl ester,2-vethyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone),2,4,6-trimethylbenzoyldiphenylphosphine oxide,2-hydroxy-2-methyl-1-phenyl-propan-1-one), and2,2-Dimethoxy-1,2-diphenylethan-1-one.
 8. A liquid crystal polymercomposition comprising, a liquid crystal; acrylic monomers including anacrylic monomer group (A) including a cyclic ring and an acrylic monomergroup (B) including a chain structure; and a photo initiator, whereinthe chain structure comprises one or more selected from the groupconsisting of 2-methylheptyl acrylate, isodecyl acrylate, and octyldecylacrylate.
 9. The liquid crystal polymer composition of claim 8, whereina content ratio between the liquid crystal and the acrylic monomers is8:2 to 9:1.
 10. The liquid crystal polymer composition of claim 9,wherein, in the acrylic monomers, a content ratio between the acrylicmonomer group (A) and the acrylic monomer group (B) is 8:2 to 9:1. 11.The liquid crystal polymer composition of claim 10, wherein a contentratio between the acrylic monomers and the photo initiator is 7:3 to9:1.
 12. The liquid crystal polymer composition of claim 8, wherein thephoto initiator comprises one selected from the group consisting of2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1),phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide,bis(.eta.5-2,4-cylcopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide,2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one,2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone,1-[9-ethyl-6-(2-methylbenzoyl)-9Hcarbazol-3-yl]-, 1-(O-acetyloxime),1-hydroxy-cyclohexyl-phenyl-ketone, oxy-phenyl-acetic acid 2-[2 oxo-2phenyl-acetoxy-ethoxy]-ethyl ester,2-vethyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone),2,4,6-trimethylbenzoyldiphenylphosphine oxide,2-hydroxy-2-methyl-1-phenyl-propan-1-one), and2,2-Dimethoxy-1,2-diphenylethan-1-one.